Aspleniaceae

Terrestrial, epiphytic, climbing or rupestral ferns of small to moderate or large size, rhizome a stout radial caudex or short-creeping, less often long-creeping, dictyostelic, young parts densely covered with clathrate, non-peltate scales. Fronds sessile to long-stipitate, the stipes not articulate to the rhizome, 2 vascular bundles at the base uniting upwards into one of +/- X-shape, the lamina simple, or pinnate to decompound, filmy to leathery, axes generally grooved, the margins of lamina and grooves decurrent with those of higher and lower orders, veins simple or forked, free to the margin or anastomosing into a continuous intramarginal vein or more copiously anastomosing without free included veinlets. Sporangia in sori elongate along the veins, protected by an elongate indusium attached along the veins and at the ends, the indusia facing the same direction, less often in pairs facing each other, rarely exindusiate, stalk for the most part uniseriate, annulus longitudinal, interrupted; spores monolete smooth to spinulose or reticulate tuberculate with a perispore.

Distribution

A cosmopolitan family of 7 - 13 genera depending on the generic concepts of the various authors, covering perhaps more than 700 species. In Papuasia there are 3 genera with c. 60 species, mostly in Asplenium.

Genera

Sori distinctly elongate along the veins; segments of fronds usually
with more than 1 vein

2

2

Sori on adjacent veins opening towards each other, often a raised
line remaining between the sori when ripe

Diplora (c. 4)

Sori all facing the same way, except in a few species with simple
fronds and then the raised line between the sori lacking

Asplenium (c. 50)

Note:

Some authors consider that these three genera should be united under a single genus, Asplenium. However there appear to be anatomical differences that support the above distinctions.

Because of the similarity of soral and indusial structure, this family has often been combined with the Athyriaceae in the past. However, taking spores, cytology, and other morphological factors into account it is now universally accepted that the families should be maintained separately.